Cytotoxic effects of permethrin in salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged females

Abstract

Because of the medical and veterinary importance of ticks and the wide use of synthetic chemical substances such as permethrin (active ingredient of Advantage® Max3 - Bayer)for their control, this study evaluated the effects of different concentrations (206, 1031 and 2062 ppm) of the acaricide on the salivary glands of Rhipicephalus sanguineus semi-engorged females. Results showed that permethrin is a potent substance that acts morpho-physiologically in the tick glandular tissue, causing changes in the acini shape intense vacuolation in acinar cells, and disruption of the tissue by cell death process, with subsequent formation of apoptotic bodies, especially at higher concentrations, thus precluding the accurate identification of different types of acini. Importantly, it is demonstrated that permethrin acts on salivary gland tissue, as well as affecting the nervous system, accelerating the process of glandular degeneration, and interfering with the engorgement process of female ticks, preventing them from completing the feeding process.

Morpho-ultrastructural alterations in the salivary glands of semi-engorged Riphicephalus sanguineus s.l. females subjected to permethrin

“…In this study, the presence of myelin figures and lysosomes (structures that should only be observed in glands in more advanced stages of engorgement) was also observed. These data corroborate Nodari et al [16][17][18], who reported that permethrin would be accelerating the degeneration of the salivary glands of the R. sanguineus s. l. females subjected to different concentrations of the product.…”

“…Thus, the ultrastructural and cytochemical data obtained in this study complement studies by Nodari et al [16][17][18], confirming the neurotoxic action [9], of permethrin. Even in lower concentrations than the ones commercially recommended, the product would act on the morphophysiology of the salivary emergent Life Sciences Research Nodari et al glands of R. sanguineus s. l. semi-engorged females, accelerating the degeneration process through atypical cell death, by apoptosis (fragmentation) and autophagy (vacuolation) simultaneously.…”

“…The ultrastructural data regarding the salivary glands of the females from the control group corroborate light microscopy analyses by Nodari et al [16][17][18] , who demonstrated that in this group the acini were intact, maintaining original shape; i.e., rounded, and presenting intact cells. The acini I cells presented a well-defined basal membrane labyrinth, as described in literature [22], with randomly distributed mitochondria throughout the cytoplasm and the presence of lipid inclusions (drops).…”

“…Considering this, the present study had the objective to cytochemically analyze the alterations in the nucleolar structure and in the ultrastructure of the salivary gland cells of R. sanguineus s. l. semi-engorged females subjected to different concentrations of permethrin (206, 1031 and 2062 ppm). Studies by Nodari et al [16][17][18] have demonstrated that this pyrethroid would accelerate the degeneration of the glandular tissue in this species.…”

“…Studies on tick salivary glands degeneration [11][12][13], mainly addressing the influence of synthetic acaricides on the morphophysiology [14][15][16][17][18] and ultrastructure, are scarce in the literature. Considering this, the present study had the objective to cytochemically analyze the alterations in the nucleolar structure and in the ultrastructure of the salivary gland cells of R. sanguineus s. l. semi-engorged females subjected to different concentrations of permethrin (206, 1031 and 2062 ppm).…”